Student achiever charges

Really bad services, you don't follow up they do not communicate. They have have been charging me lots of money for a student achiever account I've never used, they upgraded me to an expensive account without my knowledge and now I owe them R5700 in bank charges. They sent me an sms to say I should switch to a mymo account and they will write off my negative balance., which I responded yes to, first I had to go to a branch to confirm my identity, which the did not communicate to me until I called them to follow up and now they are giving me the run around about writing off the negative balance saying it's impossible. Also it would be nice for them to tell us that they upgrade our accounts at a certain age when we get tudebt achiever because of our student loans.